Development of Ag-Cu-Zn-Sn brazing filler metals with a 10 weight-% reduction of silver and same liquidus temperature

With BrazeTec BlueBraze the manufacturers in HVACR industry have an alternative filler metal with 10 weight-% less silver but same brazing temperatures. The performance of these new alloys has been evaluated in several tests. The evaluation included wetting investigations, metallographic examinations, joint strength at different temperatures and pulsation and corrosion resistance. The results of these tests will be presented in this paper.

Metallogenic Epoch of Nonferrous Metallic and Silver Deposits in the Jiaodong Peninsula, China and its Geological Significance

As China＇s most important gold-producing district, the Jiaodong Peninsula also contains copper, lead-zinc, molybdenum （tungsten）, and other nonferrous metal ore deposits, but the space-time and genetic relationships with gold deposits remain uncertain. To investigate the temporal relationship between these nonferrous metal and gold ore deposits, We collected the samples from a number of nonferrous metallic and silver deposits and metallogenetic rock bodies in the eastern Jiaodong Peninsula for isotopic dating. The results show that the Re-Os isotopic model ages of the Lengjia molybdenum deposit in Rongcheng range from 114.5 ± 1.8 Ma to 112.6 ± 1.5 Ma, with an average age of 113.6 ± 1.6 Ma; the LA-ICP-MS ^206pb/^238U ages of 33 zircons in the sericitization porphyritic monzogranite that hosts the Tongjiazhuang silver deposit in Rongcheng range between 122 Ma and 109 Ma, with a weighted mean age of 116.04 ± 0.95 Ma; the LA-ICP-MS ^206pb/^238U ages of 31 zircons in the copper metallogenic pyroxene monzodiorite that hosts the Kuangbei copper deposit in Rongcheng range from 126 Ma to 106 Ma, with a weighted mean age of 116.6 ± 1.7 Ma; and the LA-ICP-MS ^206pb/^238U ages of 19 zircons in the pyroxene monzodiorite surrounding the Dadengge gold and multimetal deposit in Weihai range from 113 Ma to 110 Ma, with a weighted mean age of 111.7 ± 0.6 Ma. All these results indicate that the metallogenic ages of the silver and nonferrous metallic deposits in the Jiaodong Peninsula are in a limited range from 118 Ma to 111 Ma. Previous studies have demonstrated that the isotopic ages of gold deposits in the Jiaodong Peninsula range from 123 Ma to 110 Ma, while Weideshanian magmatism occurred between 126 Ma to 108 Ma. Both these ranges are grossly consistent with the metallogenic ages of silver and nonferrous metallic deposits in this study, suggesting that the large-scale mineralization occurred in the Early Cretaceous when magmatic activities were strong. This epoch may be linked to the lithosphere thinning and the thermo-upwelling extension in eastern China at that time. In addition, field investigation also shows that gold and nonferrous metallic deposits are distributed nearby the Weideshanian granite, with the nonferrous metallic deposits lying within or surrounding the granite pluton and the gold deposits outside the granite pluton. We propose the following mineralization scenario： In the Early Cretaceous, an intensive lithospheric extension induced partial melting and degassing of the metasomatized lithospheric mantle, which resulted in the formation of mantle-derived fluids enriched in metal elements. During the rapid process of magma ascent and intrusion, crust-derived fluids were activated by the magmatic thermal dome and served to further extract ore-forming materials from the crust. These fluids may have mixed with the mantle-derived fluid to form a crust-mantle mixing-type ore-forming fluid. The high-temperature conditions in the center or in contact with the granitic magmatic thermal dome would have been favorable for the formation of porphyry-type, skarn-type, and hydrothermal-vein-type ores, thus forming a series of Mo（W）, Cu, and Pb-Zn deposits in the mid-eastern Jiaodong Peninsula. In contrast, the medium- to low-temperature conditions in the periphery of the magmatic thermal dome would have favored the deposition of gold （silver） ores under the appropriate physiochemical and structural conditions. The metaliogenic epoch of the molybdenum, copper, and silver deposits, and their spatio-temporal and genetic relations to the gold deposits, as demonstrated in this study, not only provide important insights to the study of regional metallogeny, our understanding of the metallogenesis of the Jiaodong type gold deposit, and the geodynamic background of the large-scale mineralization in the Jiaodong Peninsula, but also have practical value in guiding the mineral exploration.

Tectonic Dynamic Metallization of Silver-GoldHydrothermal Fluids in Proterozoic GneissTerrene Shear Zones, Suichang, Zhejiang, China

The Suichang mine is the largest silicified vein-type silver-gold mineralization system in Southeast China, whose ore bodies are controlled by shear zones developing in Lower Proterozoic gneiss terrene with initial migmatization, which is covered by Upper Jurassic and Lower Cretaceous volcanic rock system and cut by acidic igneous veins of Jurassic and Cretaceous. The conclusions are as follows: (1) The ore-forming fluid is defined as superhigh tectonic-metamorphic fluid on the base of : 1 (D)-(18O) values 2 fluid inclusions;3 trace elements of pyrite from ores. (2) The shear zone silicified orebod-ies occurred in proterozoic, Jurassic and Cretaceous, which have been transforms in part by ore-bearing comb quartz vein of volcanism.

Electrochemical Separation of Metal Silver from Industrial Wastewater

Investigation into the separation of metal silver from industrial wastewater using electrochemical cell was carried out. Wastewater from photo laboratories was collected and treated batch wise using electrolytic equipment. A constant voltage of 2.0 V and variable current in the range of 0.3 - 0.6 A at normal temperature were passed through the electrolyte for a period from 0.25 - 1.0 h. The results showed that increase in current yield an increase in the amount of metallic silver recovered with highest values of 2.3 g and 2.8 g at 0.6 A for the tested samples 1 and 2, respectively. The electrochemical separation method proved to be more reliable and economical when compared to other methods and also, reduction in environmental pollution of industrial wastewater containing high concentration of silver metal is achieved.

退役晶硅光伏组件中基于有机酸浸出银的研究

对退役晶硅光伏组件中贵金属银进行浸出研究,分别采用甲磺酸-过氧化氢体系和柠檬酸-过氧化氢体系浸出银。结果显示,在甲磺酸-过氧化氢体系中,最优工艺条件为:甲磺酸浓度40%、H_(2)O_(2)浓度10%、反应温度80℃、反应时间2.5 h,银的浸出率达到59.97%;在柠檬酸-过氧化氢体系中,最优工艺条件为:柠檬酸浓度6 g/L、H_(2)O_(2)浓度30%、反应温度80℃、搅拌速度300 r/min,银的浸出率能达到95.53%;柠檬酸体系能更有效地浸出银,反应温度和H_(2)O_(2)浓度的提高对银的浸出有促进作用。

Comparative Study between Magnetite Nanoparticles and Magnetite/Silver as a Core/Shell Nanostructure

Magnetite nanoparticles (MNPs) and magnetite/silver nanoparticles (M/Ag NPs) were synthesized by chemical co-precipitation of Fe2+ and Fe3+. In case of M/Ag NPs, MNPs (core) were separately coated by silver metal (shell) in presence of glucose as a reducing agent. The particle size and morphology of the nanoparticles were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). Magnetic properties were investigated by vibrating sample magnetometry (VSM). The superparamagnetic natures of the nanoparticles were confirmed by the absence of the hysteresis loop. Coverage with silver produced a core-shell heterostructure which weakens magnetization of MNPs, inducing an inert character to the fnal nanostructure. The surface conjugation of MNPs with silver metal has been employed in order to improve the compatibility of magnetite nanoparticles to overcome their limitations in practical applications.

取代苯甲酸根对银(Ⅰ)⁃四(4⁃吡啶基)乙烯金属有机框架材料的结构与发光性质调控

选取了1,1,2,2‑四(4‑吡啶基)乙烯(TEPE)作为桥联配体与Ag(Ⅰ)组装形成阳离子框架,通过引入五氟苯甲酸根(PFB-)或苯甲酸根(Bz-)作为客体得到2例新颖的配合物:[Ag(TEPE)(H_(2)O)](PFB)·7H_(2)O·3EtOH(1)和[Ag(TEPE)](Bz)·4H_(2)O·2EtOH(2)。通过热重分析、红外光谱和单晶X射线衍射等测试对二者的组成与结构进行分析表征。配合物1是一个二维“砖墙”式层状结构,具有经典的hcb拓扑网络。中心Ag(Ⅰ)与分别来自3个TEPE配体的3个氮原子和1个水分子配位,形成四面体的配位几何构型。PFB-客体分布于二维层间,与主体层间产生丰富的超分子相互作用。配合物2则呈现三维网络结构,Ag(Ⅰ)与分别来自4个TEPE配体的4个氮原子配位,Bz-客体填充在c轴方向形成的一维孔道中。配合物2的拓扑结构为sqc8116。在紫外光的激发下,2个配合物均表现出由阴离子客体引起的特征荧光性质。1发射红光,而2则发射蓝光。

Effects of Ga and In on the properties of cadmium-free Ag-Cu-Zn filler metal

Melting temperature, spreadability, mechanical properties and the microstructures of joints brazed with silver-base filler metals including different amounts of Ga and/or In were studied respectively in this paper, and the results show that the melting temperature of the silver-base filler metals is decreased, spreadability of the silver-base filler metals is improved, and the microstructures of silver-base filh, r metals are refined obviously with the addition of Ga and/or In. Using copper and brass plates as base metal and brazing with flame method, the mechanical properties of the lap-joint and butt joint were also examined and analyzed respectively, and the results indicate that the fracture position of two kinds of brazed joints occurred on the base metal, except for the lap-joint of brass, which shows better mechanical properties of the joints brazed with the silver- based filler metals including Ga. For the lap-joint of brass, the tensile strength gradually increased with the increase of Ga content, while the addition of In has little effect on mechanical properties. It is also found that the best comprehensive properties of cadmium-free Ag-Cu-Zn filler metals are obtained when Ga content is about 3.0 wt. % and In content is between 1.5 wt. % and 2. 0 wt. %.

Molecular recognition by gold, silver and copper nanoparticles

The intrinsic physical properties of the noble metal nanoparticles,which are highly sensitive to the nature of their local molecular environment,make such systems ideal for the detection of molecular recognition events.The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles.In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization.A brief discussion of the three common methods of functionalization:Electrostatic adsorption;Chemisorption;Affinity-based coordination is given.In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition.In the main section the various types of capping agents for molecular recognition;nucleic acid coatings,protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications.Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition.For the proteins the recognition properties of antibodies form the core of the section.With respect to the supramolecular systems the cyclodextrins,calix[n]arenes,dendrimers,crown ethers and the cucurbitales are treated in depth.Finally a short section deals with the possible toxicity of the nanoparticles,a concern in public health.

Characterization and Biosorption Performance of Silver by Bacillus Licheniformis

The demand of silver is increasing rapidly in recent decades, because silver and its related products are widely used in modern industry and decoration. It is necessary to recover silver from waste water using an efficient and environmental friendly method due to its environmental and economic benefits. In this paper, we eliminated the interference of Cl-and light conditions, and then studied the characterization and biosorption performance of silver by Bacillus licheniformis. The max biosorption amount was 87.4 mg/g(dry weight) with the initial Ag+concentration of 100 mg/L at pH 6.0. XRD pattern showed that the product was an amorphous compound. SEM/EDS-mapping and FT-IR results implied that phosphate, amino and carboxyl groups located on the cell walls involved in the biosorption of Ag^+. The XPS spectra result showed that the value of EB of Ag 3d_(5/2_(367.51 eV) corresponded to the energy values for Ag(Ⅰ), and indicated Ag^+ adsorbed to the surface of cell still maintained mono-valence. The results confirm that B. licheniformis just adsorb Ag+ but cannot covert soluble Ag^+ to silver nano-particles(AgNP).

Anti-tarnish property of sterling silver alloy with yttrium addition

It has been demonstrated that sterling silver alloy is a widely used material in the jewelry industry. The anti-tarnish property is one of the most important properties of this material. In this work, the effect of yttrium on the corrosion resistance, and tarnish resistance properties of sterling silver alloy were investigated with the use of CIE-LAB uniform color scale, which gained acceptance as an effective way to assess color. To better understand the mechanism of the effect, the distribution of yttrium in the alloy was analyzed by mainly segregating in gaps among dendrite crystals and grain boundary. An increase in yttrium content in sterling silver alloy resulted in a decrease in the amount of eutectic structure. The tarnish and corrosion resistance of sterling silver were improved with yttrium content increase. However, too high yttrium content will lead to poor anti-tarnish properties.

Synergistic interaction of metal–acid sites for phenol hydrodeoxygenation over bifunctional Ag/TiO_2 nanocatalyst

The use of silver metal for hydrodeoxygenation(HDO) applications is scarce and different studies have indicated of its varying HDO activity. Several computational studies have reported of silver having almost zero turnover frequency for HDO owing to its high C\\O bond breaking energy barrier and low carbon and oxygen binding energies.Herein this work, titania supported silver catalysts were synthesized and firstly used to examine its phenol HDO activity via experimental reaction runs. BET, XRD, FESEM, TEM, EDX, ICP–OES, Pyridine-FTIR, NH_3-TPD and H_2-TPD analyses were done to investigate its physicochemical properties. Phenomena of hydrogen spillover and metal–acid site synergy were examined in this study. With the aid of TiO_2 reducible support, hydrogen spillover and metal–acid site interactions were observed to a certain extent but were not as superior as other Pt, Pd, Ni-based catalysts used in other HDO studies. The experimental findings showed that Ag/TiO_2 catalyst has mediocre phenol conversion but high benzene selectivity which confirms the explanation from other computational studies.

Synthesis and Crystal Structure of a Two-dimensional Silver Framework Constructed by H_2idc (H_2idc = Iminodiacetic Acid)

A new compound formulated [Ag2(idc)](NO3)?H2O (H2idc = iminodiacetic acid) was synthesized under mild conditions and characterized by IR spectrum and single-crystal X-ray diffraction. The crystal crystallizes in the monoclinic system, space group of P21/n with a = 5.5029(2), b = 11.1316(5), c = 15.5319 (1) ?, β = 96.038(3)o, V = 946.15(6) ?3, Z = 4, R = 0.0619 and wR = 0.1606. Its structure is a 2D polymer, whose repeat units consist of dinuclear silver cluster coordinated by two bridging iminodiacetic acids. In the complex, the Ag(I) ions adopt three coordinate fashions, and the Ag-Ag metal-metal contacts of 2.8418 ? are observed.

A new approach for deposition of silver film from AgCl through successive ionic layer adsorption and reaction technique

An attempt was made to deposit thin film of silver onto the glass substrate by using Ag Cl precursor, instead of conventional precursor AgNO_3 with vitamin C by inexpensive and convenient successive ionic layer adsorption and reaction(SILAR) method. The deposited silver thin film was characterized by X-ray diffraction(XRD) analysis, scanning electron microscope(SEM), UV-visible and electrical I-V study. The diffraction study showed FCC structure of metallic silver in good agreement with the standard values of JCPDS(04–0783). SEM reveals flower like nano particles produced on the substrate. The surface plasmon resonance(SPR) peak in the UV-visible spectrum shows maximum absorption at 350 nm. The film shows an ohmic behavior and its electrical resistivity was found ~103 ?·cm at room temperature.

Exploration and Mapping of Metalliferous Black Shales in the Saghro Temporary Subsidence Zones (Anti-Atlas, Morocco)

The Saghro massif constitutes a vast metallogenic province with numerous deposits and shows of base metals (lead, zinc, copper) and precious metals (gold and silver), besides various useful substances (talc, pyrophyllite, barite, fluorite). Silver/lead occurrences are concentrated along the Cryogenian Imiter series and moderately at Boumalne and Sidi Flah. Copper occupies the plutonic intrusions and intrusive rocks of the East-Central Saghro while barite deposits are widespread throughout the Cambrian cover of the East Saghro in contact with the Ediacaran basement. To justify this distribution, the new contributions of the cartography and the organic geochemistry of the black shales of Jbel Saghro have clearly shown the particularity of the Imiter black shales in terms of the richness in organic matter (TOC = 0.18%), the blackish color and the friability. The Boumalne and Sidi Flah groups present some similarities with the Imiter group, such as the sub-equatorial structuring, the friable pelites and the richness in organic matter (Boumalne TOC = 0.11% and SidiFlah TOC = 0.16%), which is a quite good show that requires to reinforce the exploration works. For Western Saghro in the Iknioun and Qalaa’t M’Gouna groups, the variations in the thickness of the volcanic cover show an irregular paleotopography with hard, greenish, organic-poor pelitic sediments (TOC = 0.01 to 0.04%). We can conclude that the formation of Imiter-type silver concentrations requires the combination of the sedimentological, the volcanic and structural factors. For Imiter-type silver these factors are: a fine pelitic and argillic casing deposited in a confined environment, a basic volcanism source of metals and other intermediate to acid generated by the hydrothermalism and heat, a convenable paleotopography and a network of fracturations to trap the mineralizations.

Optical Properties of Chiral Azo-Schiff Base Mn(II) and Zn(II) Complexes with Silver Nanoparticles

Herein we have originally designed chiral azo-salen Mn(II) and Zn(II) complexes for interacting silver nanoparticles (AgNPs) exhibiting localized surface plasmon resonance (LSPR). Understanding excited state and reaction intermediate during light irradiation to return to ground state may be important for such composite systems. Therefore, we investigated such optical properties for systems using time-resolved luminescence and transient absorption measurements. DMSO solutions of the four newly prepared and characterized complexes (MMn, MZn, CMn, and CZn) and ethanol solutions of the composite materials of each complex with AgNPs were served for optical measurements. The time-correlated single photon counting (TCSPC), the streak camera which is much shorter period of time than TCSPC and transient absorption measurement, was performed for the eight samples. The fluorescence lifetime of the sole complexes and the composite materials with AgNPs was derived from curve-fitting analysis of luminescence decay curves of TCSPC. Lifetime of the composite systems with AgNPs was longer than that of the corresponding sole metal complexes for three cases. It was revealed that composite systems may go through three reaction intermediates during relaxation from excited state to ground state.

改性黑药类捕收剂强化浮选玉龙铅锌矿中伴生银的无碱工艺研究

针对玉龙铅锌矿浮选过程中伴生银矿物回收率不高等问题,进行了新型捕收剂下无碱铅银浮选工艺研究。研究结果表明,在磨矿细度为-74μm占65%时,抑制剂采用亚硫酸钠与硫酸锌,捕收剂采用改性黑药类捕收剂CY-1,可实现无碱条件下铅银精矿中银回收率的显著提升。闭路实验获得了含Pb 52.05%、Ag 4 866 g/t的铅银精矿,铅、银回收率分别为91.76%和84.43%。与乙硫氮+丁铵黑药为组合捕收剂时的高碱工艺相比,铅、银回收率分别提高了2.5和6百分点。该工艺消除了浮选过程中石灰对银矿物的抑制,有助于强化铅锌矿伴生稀贵金属的综合回收,提升资源的综合利用效率。

NEW METHOD OF EXTRACTING GOLD AND SILVER FROM HIGH SILVER-GOLD CONCENTRATES

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基于AIE分子-适配体探针的银离子检测研究

重金属污染是当下严峻的环境问题。传统的水体重金属检测方法存在操作复杂、慢速且高成本的问题,因此,开发一种简单高效、低成本的新型检测技术意义重大。本文以银离子作为检测对象,利用核酸适配体技术和聚集诱导发光(Aggregation-Induced Emission,AIE)技术,将特定的核酸适配体与具有聚集诱导发光效应的阳离子型AIE分子(四苯基乙烯衍生物TPEDPy2CH3I)结合,构建了一种针对水体中银离子浓度检测的新型复合探针体系。该检测方法具有高选择性、快速响应和低检测限等特点,同时也能够为水体中其他重金属离子的检测提供一定的参考和启发。

水性铝银浆行业现状分析及未来发展趋势

随着国家环保要求的不断提高,开发绿色环保型涂料变得日益紧迫,传统的溶剂型涂料正在被水性涂料所取代。水性铝银浆作为一种常见的金属颜料,因其良好的装饰性和金属光泽,在水性涂料、水性墨等领域得到越来越广泛的应用。为使人们对水性铝银浆有一个全面的认识,本文对该行业做较为系统的概述。首先介绍水性铝银浆行业的发展现状,主要包括制备工艺、品质检测、应用领域、优缺点及使用注意事项等;其次介绍水性铝银浆的市场前景和发展趋势;最后给出水性铝银浆行业的发展建议。